I keep most of my yarn stored in one of these babies from Ikea. Works in Progress are stored in a large basket on the floor, or in one of the cubby holes in my coffee table. I can't tell you how much I love this coffee table - I've got various baskets and boxes in most of those holes, holding everything from random craft supplies, my drop spindle and roving, ball bands and random scrap yarns, and my sad & forlorn Central Park Hoodie WIP.
On your right, we have the copper red yarn I previously wrote about winding, plus my New Zealand wool (first "real" yarn purchase, ie not Micheals or Joanns). There's some mohair in the ziploc bag, which I can't seem to make anything out of, and an assortment of ribbon yarns that I bought at an lys for $1 each. Course now I don't know what to do with them. And on the far left of this picture is my collection of cheap yarn - Lions Brand and Patons. I use them for swatches, mainly, and things that need to be washable like toys. Someday I'll use it to knit up some squares for charity, I think.
The good news is I've used a bit of this yarn for personal projects and Christmas knitting. I've made a real effort to knit only from my stash, both for monetary and available space reasons. Hopefully one day I'll be able to reference these pictures and say that all of this yarn has been used. Course by then, I'll have bunches more waiting for me!
On a random cat note, Emma has begun attacking my knitting and playing with my yarn while I'm at work. *sigh* So I'm adding covers to many of my baskets and hiding WIPs out of her reach. I think it's her kitty way of saying "I hate it when you're at work all day and then come home and play with this yarn instead of me. Bah!" And she has a ridiculous passion for mohair. And super nice yarn. But not acrylics, oh no. My baby knows her expensive yarns.